These studies are designed to evaluate the clinical benefits achieved by iron chelation in patients with chronic iron overload. Desferrioxamine is administered by subcutaneous infusion and iron removal is determined by quantitation of urinary iron excretion and careful recording of the total iron administration by transfusion. Those patients who had no evidence of cardiac disease were randomized to receive either ascorbic acid (3 mg/kg) or placebo. Sixty-five patients were included in the long-term chelation trial and of those 49 were randomized to the ascorbic acid study. Twelve patients have been followed for a minium of three years and many for four or five years. The final annual evaluation for this trial will be completed during the next several months. These data will be analyzed to determine whether a clinically significant difference is present between the two groups, namely those that receive ascorbic acid compared to placebo.